Reservoir tank

ABSTRACT

A reservoir tank includes: a tank body in which cooling fluid is stored; an inflow pipe for sending the cooling fluid into the tank body; a discharge pipe for discharging the cooling fluid from the tank body; and a columnar member erected inside the tank body, in which the inflow pipe is connected to the tank body vertically below a liquid level of the cooling fluid stored inside the tank body, the columnar member extends in a substantially vertical direction when viewed along a center line of the inflow pipe, and a part of the columnar member is disposed on an extension line of the center line of the inflow pipe.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority from Japanese Patent Application No. 2020-162929 filed with the Japan Patent Office on Sep. 29, 2020, and from Japanese Patent Application No. 2020-169517 filed with the Japan Patent Office on Oct. 7, 2020, the entire contents of both of which are hereby incorporated by reference.

BACKGROUND 1. Technical Field

One aspect of the present disclosure relates to a reservoir tank.

2. Related Art

Liquid-cooled cooling systems are used for cooling internal combustion engines, electric elements, electronic boards, and the like. In the liquid-cooled cooling system, heat is collected from a member to be cooled by circulating a cooling fluid, which dissipates the heat through a heat radiator, in order to cool the member to be cooled. In the liquid-cooled cooling system, a cooling fluid tank, that is, the reservoir tank, may be provided in a cooling fluid circuit for circulating the cooling fluid. The reservoir tank is used to compensate for a decrease in the cooling fluid due to vaporization or the like, and to absorb a volume change of the cooling fluid due to a temperature change. When air bubbles are generated in the cooling fluid, cooling efficiency may decrease. Therefore, the bubbles in the cooling fluid may be separated by the reservoir tank, that is, gas-liquid separation may be performed.

For example, in a technique disclosed in JP-A-2005-248753, rectangular baffle plates are arranged in a reservoir tank body so as to have a windmill shape in a specific direction. JP-A-2005-248753 discloses that according to the reservoir tank, the bubbles can be separated from the cooling fluid without increasing water flow resistance and complicating its structure.

SUMMARY

A reservoir tank includes: a tank body in which cooling fluid is stored; an inflow pipe for sending the cooling fluid into the tank body; a discharge pipe for discharging the cooling fluid from the tank body; and a columnar member erected inside the tank body, in which the inflow pipe is connected to the tank body vertically below a liquid level of the cooling fluid stored inside the tank body, the columnar member extends in a substantially vertical direction when viewed along a center line of the inflow pipe, and a part of the columnar member is disposed on an extension line of the center line of the inflow pipe.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a vertical cross-sectional view illustrating a structure of a reservoir tank of a first embodiment;

FIG. 2 is a horizontal cross-sectional view illustrating the structure of the reservoir tank of the first embodiment;

FIG. 3 is a horizontal cross-sectional view illustrating an operation of the reservoir tank of the first embodiment;

FIG. 4 is a vertical cross-sectional view illustrating the operation of the reservoir tank of the first embodiment;

FIG. 5 is a horizontal cross-sectional view illustrating the structure and the operation of the reservoir tank of a first modification;

FIG. 6 is a vertical cross-sectional view illustrating the structure of the reservoir tank of a second embodiment;

FIGS. 7A to 7F are horizontal cross-sectional views illustrating a shape of a modification of a columnar member;

FIG. 8 is a vertical cross-sectional view illustrating the structure of the reservoir tank of a third embodiment;

FIG. 9 is a vertical cross-sectional view illustrating the operation of the reservoir tank of a reference example; and

FIG. 10 is a vertical cross-sectional view illustrating the structure of the reservoir tank of a fourth embodiment.

DETAILED DESCRIPTION

In the following detailed description, for purpose of explanation, numerous specific details are set forth in order to provide a thorough understanding of the disclosed embodiments. It will be apparent, however, that one or more embodiments may be practiced without these specific details. In other instances, well-known structures and devices are schematically shown in order to simplify the drawing.

In recent years, in order to improve performance of a cooling system, there has been a demand for increasing a flow rate of cooling fluid passing through a reservoir tank as disclosed in JP-A-2005-248753. However, it has been found that when the flow rate of the cooling fluid passing through the reservoir tank increases in the reservoir tank as disclosed in JP-A-2005-248753, the cooling fluid flowing into a tank body tends to be undulating and turbulent, and thus air in the tank is easily entrained in the cooling fluid and thereby generate air bubbles, so that it is difficult to obtain an expected level of gas-liquid separation effect.

Specifically, in recent years, as the demand for miniaturization of the reservoir tank has increased, turbulence of the cooling fluid inside the tank body is likely to occur.

An object of the present disclosure is to suppress turbulence of a liquid surface inside the tank body of the reservoir tank and to suppress generation of air bubbles inside the reservoir tank.

As a result of intensive studies, the inventors have found that it is possible to suppress the turbulence of the liquid surface inside the tank body by allowing the cooling fluid flowing out of an inflow pipe to flow into the cooling fluid inside the tank body vertically below the liquid level of the cooling fluid, and by providing a columnar member in the tank body and arranging a part of the columnar member on an extension line of a center line of a flow of the cooling fluid flowing out from the inflow pipe, and have completed a technology of the present disclosure.

A reservoir tank according to an aspect of the present disclosure includes: a tank body in which cooling fluid is stored; an inflow pipe for sending the cooling fluid into the tank body; a discharge pipe for discharging the cooling fluid from the tank body; and a columnar member erected inside the tank body, in which the inflow pipe is connected to the tank body vertically below a liquid level of the cooling fluid stored inside the tank body, the columnar member extends in a substantially vertical direction when viewed along a center line of the inflow pipe, and a part of the columnar member is disposed on an extension line of the center line of the inflow pipe (first aspect).

In the first aspect, it is preferred that the reservoir tank has a plurality of the columnar members including a first columnar member and a second columnar member, in which the plurality of columnar members is arranged so that a flow of the cooling fluid flowing from the inflow pipe into the tank body is divided in a substantially horizontal direction by the first columnar member, and the divided flow of the cooling fluid is further divided in the substantially horizontal direction by the second columnar member (second aspect). Further, in the first aspect, a position in which the extension line of the center line of the inflow pipe and the columnar member intersect is preferably vertically below the liquid level of the cooling fluid (third aspect). Furthermore, in the third aspect, it is preferred that the center line of the inflow pipe extends in a substantially horizontal direction, and the columnar member extends in a substantially vertical direction (fourth aspect).

Further, in any of the first to fourth aspects, the columnar member is preferably disposed to connect a top wall and a bottom wall of the tank body (fifth aspect). Further, in any of the first to fourth aspects, a cross-sectional shape of the columnar member in a horizontal plane is preferably convex toward an upstream side of a flow of the cooling fluid (sixth aspect). Furthermore, in any of the first to fourth aspects, a width of the columnar member when viewed along the center line of the inflow pipe is preferably 0.5 times or more and 3 times or less a diameter of the inflow pipe (seventh aspect).

Further, a reservoir tank according to another aspect of the present disclosure includes: a tank body in which cooling fluid is stored; an inflow pipe for sending the cooling fluid into the tank body; a discharge pipe for discharging the cooling fluid from the tank body; and a columnar member erected inside the tank body. The inflow pipe extends inside the tank body and is opened to an inner space of the tank body vertically below a liquid level of the cooling fluid stored inside the tank body, the columnar member extends in a substantially vertical direction when viewed along a center line of a pipe line of the inflow pipe at a portion where the inflow pipe is opened, and a part of the columnar member is disposed on an extension line of the center line of the pipe line of the inflow pipe at the portion where the inflow pipe is opened (eighth aspect).

According to the first and eighth aspects of the present disclosure, since the turbulence of the liquid surface inside the tank body is suppressed, the generation of the bubbles inside the reservoir tank can be suppressed.

According to the second to fourth aspects, an effect of suppressing the turbulence of the liquid surface and an effect of suppressing the generation of the bubbles are further improved.

Further, according to the fifth aspect, vibration of the columnar member is suppressed. As a result, generation of noise from the reservoir tank is suppressed.

Further, according to the sixth aspect and the seventh aspect, the effect of suppressing the turbulence of the liquid surface and the effect of suppressing the generation of the bubbles are further improved.

Furthermore, according to the eighth aspect, it is also possible to increase a degree of freedom in arranging the inflow pipe in the reservoir tank.

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings, taking the reservoir tank provided in a liquid-cooled cooling system for an internal combustion engine of an automobile as an example. The technology of the present disclosure is not limited to individual embodiments described below, but may also be implemented as modified embodiments below. Applications of the liquid cooling type cooling system are not limited to the internal combustion engine, but may be applications for cooling an electric element such as a power element and an inverter, and an electric component such as an electronic circuit board.

FIGS. 1 and 2 illustrate a structure of a reservoir tank 10 of a first embodiment. FIG. 1 illustrates a vertical cross-sectional view of the reservoir tank 10. FIG. 2 illustrates a horizontal cross-sectional view of the reservoir tank 10. The vertical cross-sectional view of FIG. 1 is an X-X cross-sectional view taken along a vertical plane through a line X-X of FIG. 2. Further, the horizontal cross-sectional view of FIG. 2 is a Y-Y cross-sectional view taken along a horizontal plane through a line Y-Y of FIG. 1.

The reservoir tank 10 is configured to include a hollow tank 17, and an inflow pipe 15 and a discharge pipe 16 connected to the tank. The reservoir tank 10 used in a cooling fluid circuit of the liquid-cooled cooling system is disposed and connected in the cooling fluid circuit of the liquid-cooled cooling system so that the cooling fluid flows from the inflow pipe 15 into the hollow tank 17, and the cooling fluid flows out of the hollow tank 17 through the discharge pipe 16.

In the vertical cross-sectional view of FIG. 1, an upper side of the figure shows a vertically upper side. In the present embodiment, a lower case 11 and an upper case 12 are integrated to form the reservoir tank 10. The lower case 11 and the upper case 12 are integrated to form a hollow tank body 17. In the present embodiment, an inflow pipe 15 and a discharge pipe 16 are integrally molded in the lower case 11. In this regard, the inflow pipe 15 and the discharge pipe 16 may be integrated with the tank body 17 by a manufacturing method different from an integral molding.

A cooling fluid L is stored in the tank body 17. Air is stored in a vertically upper portion of the tank body 17.

The inflow pipe 15 is connected to the tank body 17 vertically below a liquid level (liquid surface) S of the cooling fluid stored inside the tank body 17. With such a configuration, the cooling fluid sent from the inflow pipe 15 flows directly into the cooling fluid stored in the tank (that is, without passing through the air).

Although not essential, in the present embodiment, the inflow pipe 15 is provided outside the tank body 17 in a straight tubular shape. For example, as in a fourth embodiment described below, the inflow pipe may be extended inside the tank body.

The discharge pipe 16 is also connected to the tank body 17 vertically below the liquid level S of the cooling fluid stored inside the tank body 17. With such a configuration, the cooling fluid is efficiently discharged from the tank body 17 through the discharge pipe 16.

A columnar member 14 is erected inside the tank body 17. In the present embodiment, one columnar member 14 is erected to extend in the substantially vertical direction. The plurality of columnar members may be provided as in a modification described below. Further, as in other embodiments described below, the columnar member may be inclined with respect to the vertical direction.

The columnar member 14 extends in the substantially vertical direction when viewed along a center line m of the inflow pipe 15. The columnar member 14 does not have to extend exactly in the vertical direction. It can be said that the columnar member 14 extends in the substantially vertical direction if it is inclined in a range of about 30 degrees or less from the vertical direction. When the inflow pipe 15 is a bent or folded pipe, the center line of the inflow pipe 15 near a connecting portion with the tank body 17 (a portion of the inflow pipe 15 in which the cooling fluid flows into the tank body 17) may be considered as the center line m of the inflow pipe 15.

A part of the columnar member 14 is disposed on the extension line of the center line m of the inflow pipe 15. With this configuration, a jet of the cooling fluid flowing from the inflow pipe 15 into the tank body 17 flows to hit the part of the columnar member 14, and is divided to flow substantially in the horizontal direction so as to avoid the columnar member 14 (FIG. 3).

Although not essential, in the present embodiment, the columnar member 14 has a hollow shape having a substantially D-shaped cross-section (cross-section in the horizontal plane). Then, the columnar member 14 is provided so that a cylindrically curved surface of the columnar member 14 faces the inflow pipe 15. As will be described below, the columnar member 14 may have another shape.

Although not essential, as in the present embodiment, a position in which the extension line of the center line m of the inflow pipe 15 and the columnar member 14 intersect is preferably vertically below the liquid level S of the cooling fluid. The position in which the extension line of the center line m of the inflow pipe 15 and the columnar member 14 intersect may be substantially the same height in the vertical direction as the liquid level S of the cooling fluid. More preferably, the position in which the extension line of the center line m of the inflow pipe 15 and the columnar member 14 intersect is vertically below a position in which the inflow pipe 15 is connected to the tank body 17.

Further, although not essential, it is preferred that the center line m of the inflow pipe 15 extends substantially in the horizontal direction and the columnar member 14 extends in the substantially vertical direction as in the present embodiment.

Further, although not essential, it is preferred that the columnar member 14 is disposed to connect the top wall and the bottom wall of the tank body 17 as in the present embodiment. As in the present embodiment, it is particularly preferred that the columnar member 14 is divided into a component on the lower case side and a component on the upper case side, and the divided components of the columnar member 14 are joined (preferably welded) to each other.

Further, although not essential, it is preferred that the cross-sectional shape of the columnar member 14 in the horizontal plane is convex toward the upstream side of the flow of the cooling fluid as in the present embodiment.

Further, although not essential, it is preferred that, as in the present embodiment, a width D2 of the columnar member 14 when viewed along the center line m of the inflow pipe 15 is 0.5 times or more and 3 times or less a diameter (an inner diameter on a side opened to an inside of the tank body 17) d1 of the inflow pipe 15, that is, 0.5*d1≤D2≤3*d1 is satisfied. It is particularly preferred that 1*d1≤D2≤1.5*d1 is satisfied. In the present embodiment, D2=1.3*d1 is satisfied. If 0.5*d1≤D2, a flow dividing effect by the columnar member is likely to be sufficiently obtained. Further, if D2≤3*d1, it is possible to suppress the flow of the cooling fluid from hitting the columnar member 14 hard and heading vertically upward. As a result, the turbulence of the liquid surface of the cooling fluid can be suppressed more effectively.

As long as the reservoir tank 10 can be configured by the tank body 17, the columnar member 14, the inflow pipe 15, and the discharge pipe 16, how is the above-mentioned structure of the reservoir tank 10 specifically divided into specific parts and how to assemble the reservoir tank 10 from those parts (what constituent members (components) are used to assemble the reservoir tank 10) are not particularly limited. In the present embodiment, the above-described structure of the reservoir tank 10 is realized by dividing the reservoir tank 10 into two parts of the lower case 11 and the upper case 12, and assembling them. In this regard, the above-mentioned structure of the reservoir tank 10 may be realized by other constituent members. For example, the above-mentioned structure of the reservoir tank 10 may be realized by forming constituent members such that the tank body 17 is divided into two in the vertical plane, and assembling them.

Further, in the first embodiment, a material forming the reservoir tank 10 and a method for manufacturing the reservoir tank 10 are not particularly limited. The reservoir tank 10 can be manufactured by a known material and a known manufacturing method. Typically, the reservoir tank 10 is formed using a thermoplastic resin such as a polyamide resin as a main material. The material, reinforcing structure, and the like of the reservoir tank 10 are determined depending on the type, temperature, pressure, and the like of the cooling fluid to be used. Typically, the reservoir tank 10 can be manufactured by respectively forming members corresponding to the lower case 11 and the upper case 12 by injection molding, and by integrating the members by vibration welding, hot plate welding or the like.

In this case, it is preferred that the inflow pipe 15, the discharge pipe 16, and the columnar member 14 are integrally molded with the lower case 11 or the upper case 12. Alternatively, the inflow pipe 15, the discharge pipe 16, and the columnar member 14 may be formed as members separate from the lower case 11 or the upper case 12, and may be integrated with the lower case 11 or the upper case 12 by later assembly.

The operation and effect of the reservoir tank 10 of the first embodiment will be described. According to the reservoir tank 10 of the first embodiment, it is possible to suppress the turbulence of the liquid surface inside the tank body 17, and to suppress the generation of the bubbles.

FIG. 9 illustrates the flow of the cooling fluid inside the tank body in the reservoir tank without the columnar member as a reference example. A configuration of the reference example of FIG. 9 is the same as that of the reservoir tank 10 of the first embodiment except that the columnar member 14 is not provided.

In a reservoir tank 99 of the reference example, when the cooling fluid vigorously flows therein from the inflow pipe, the cooling fluid flowing into the tank body (a flow Q of the cooling fluid flowing therein is indicated by a white arrow) directly goes straight, and violently hits a tank wall facing the inflow pipe. Thus, the cooling fluid is dispersed upward and flows. Due to this upward flow, the liquid surface of the cooling fluid inside the tank body violently undulates. This violent undulation causes air to get caught in the cooling fluid. As a result, the bubbles are generated.

The bubbles in the cooling fluid reduce circulation efficiency of the cooling fluid and heat transport efficiency of the cooling fluid. Therefore, the generation of the bubbles in the cooling fluid leads to a reduction in cooling performance of a cooling system.

In contrast, in the reservoir tank 10 of the first embodiment, the inflow pipe 15 is connected to the tank body 17 vertically below the liquid level S of the cooling fluid. Further, the columnar member 14 is erected inside the tank body 17. The columnar member 14 extends in the substantially vertical direction when viewed along the center line m of the inflow pipe 15. Then, a part of the columnar member 14 is disposed on the extension line of the center line m of the inflow pipe 15. Therefore, the turbulence of the liquid surface inside the tank body 17 is suppressed. As a result, the generation of the bubbles inside the reservoir tank 10 can be suppressed.

That is, in the reservoir tank 10 of the first embodiment, the flow Q of the cooling fluid flowing therein from the inflow pipe 15 directly flows into the cooling fluid stored in the tank body 17. Further, the cooling fluid flowing therein from the inflow pipe 15 flows to hit the columnar member 14, and is divided and flows in the substantially horizontal direction so as to avoid the columnar member 14 as illustrated in FIG. 3. Due to this division, a vigorous flow of the cooling fluid flowing therein from the inflow pipe 15 is dispersed by the columnar member 14 and weakened. As a result, the weakened flow of the cooling fluid L hits the wall surface of the tank body 17. Therefore, the violent undulation of the liquid surface S as in the reference example of FIG. 9 is suppressed. Therefore, in the reservoir tank 10 of the first embodiment, the turbulence of the liquid surface inside the tank body 17 is suppressed. As a result, the generation of the bubbles inside the reservoir tank 10 can be suppressed (FIG. 4).

From the viewpoint of better suppressing the generation of the bubbles inside the reservoir tank by better suppressing the turbulence of the liquid surface inside the tank body 17, a configuration such as a reservoir tank 19 of a first modification illustrated in FIG. 5 may be used. The reservoir tank 19 has a plurality of columnar members 14 a, 14 b, and 14 b. It is preferred that the columnar members 14 a, 14 b, and 14 b are arranged such that the flow of the cooling fluid flowing from the inflow pipe 15 into the tank body 17 is divided into two by the first columnar member 14 a in the substantially horizontal direction, and the divided flow of the cooling fluid is further divided into two in the substantially horizontal direction by the second columnar member 14 b. Two, three, four or more columnar members may be provided. The columnar members may be configured to divide the flow of the cooling fluid into two, or may be configured to divide the flow of the cooling fluid into three or more.

According to the configuration such as the reservoir tank 19 of the first modification, the flow of the cooling fluid is further dispersed and divided, to be a gentle flow. Therefore, the effect of suppressing the turbulence of the liquid surface inside the tank body 17 and the effect of suppressing the generation of the bubbles inside the reservoir tank 19 can be further improved. Further, when the columnar members are provided, it is preferred that the columnar members are arranged as in an arrangement of bowling pins with respect to the direction of the flow of the cooling fluid from the inflow pipe 15.

Further, from the viewpoint of better suppressing the generation of the bubbles inside the reservoir tank by better suppressing the turbulence of the liquid surface inside the tank body 17, it is preferred that the position in which the extension line of the center line m of the inflow pipe 15 and the columnar member 14 intersect is vertically below the liquid level S of the cooling fluid. In this case, the cooling fluid flowing therein from the inflow pipe 15 is suppressed from vigorously blowing out upward beyond the liquid level of the cooling fluid. Therefore, the turbulence of the liquid surface inside the tank body is better suppressed.

Further, from the viewpoint of better suppressing the generation of the bubbles inside the reservoir tank by better suppressing the turbulence of the liquid surface inside the tank body 17, it is preferable that the center line m of the inflow pipe 15 extends substantially in the horizontal direction, and the columnar member 14 extends in the substantially vertical direction. With such a configuration, the flow of the cooling fluid flowing therein from the inflow pipe 15 is satisfactorily divided in the substantially horizontal direction by the columnar member 14, and is difficult to flow in the vertical direction. Therefore, the turbulence of the liquid surface inside the tank body can be better suppressed.

Further, when the columnar member 14 is disposed to connect the top wall and the bottom wall of the tank body 17 as in the reservoir tank 10 of the first embodiment, an effect of suppressing the generation of noise from the reservoir tank 10 is also obtained, since the vibration of the columnar member 14 is suppressed. The cooling fluid hits the columnar member 14 as the jet. Therefore, if the columnar member 14 is erected like a cantilever, the columnar member 14 tends to vibrate, and the noise may be generated from the reservoir tank 10. When the columnar member 14 is disposed like a double-supported beam so as to connect the top wall and the bottom wall of the tank body 17, rigidity of a portion of the columnar member 14 where the flow of the cooling fluid hits is increased. As a result, since the vibration of the columnar member 14 is suppressed, the generation of noise from the reservoir tank 10 is suppressed.

The aspects of the present disclosure are not limited to the above embodiments, but can be implemented with various modifications. Hereinafter, other embodiments of the present disclosure will be described. In the following description, portions different from the above embodiment will be mainly described, and the same portions will be denoted by the same reference numerals and detailed description thereof will be omitted. Further, the embodiments can be implemented by combining some of them or replacing some of them.

FIG. 6 illustrates a reservoir tank 20 of a second embodiment. FIG. 6 is a vertical cross-sectional view of the reservoir tank 20 corresponding to FIG. 1 in the first embodiment. The reservoir tank 20 of the second embodiment is different from the reservoir tank 10 of the first embodiment, in a direction of an inflow pipe 25 and a shape of a columnar member 24. Other configurations of the reservoir tank 20 are the same as those of the reservoir tank 10 of the first embodiment.

In the reservoir tank 20 of the second embodiment, the inflow pipe 25 is provided to be inclined vertically downward from the outside to the inside of a tank body 27. If the inflow pipe 25 is inclined slightly downward, the turbulence of the liquid surface inside the tank body 27 may be better suppressed. In the present embodiment as well, the discharge pipe 26 is provided to head vertically downward from the bottom wall of the tank body 27. However, a position and a direction of the discharge pipe 26 can be changed.

Further, in the reservoir tank 20 of the second embodiment, the columnar member 24 has a chevron cross-section as illustrated in FIG. 7A. Even with such a columnar member 24, as in the reservoir tank 10 of the first embodiment, it is possible to suppress the turbulence of the liquid surface inside the tank body 27 and to suppress the generation of the bubbles inside the reservoir tank 20.

FIGS. 7B to 7F illustrate examples of cross-sectional shapes in the horizontal plane of the columnar members according to other embodiments. In FIGS. 7A to 7F, white arrows indicate the direction of the flow of the cooling fluid from the inflow pipe 25.

The columnar member 24 may be a columnar member 24 having a chevron cross-section (V-shaped cross-section) as illustrated in FIG. 7A. Further, the columnar member may be a columnar member 24 b having a circular cross-section (hollow cylindrical cross-section) as illustrated in FIG. 7B. Further, the columnar member may be a solid member, for example, a columnar member having a solid columnar cross-section. Furthermore, the columnar member may be a prismatic member, an elliptical columnar member, a conical member, or a pyramidal member.

Further, the columnar member may be a columnar member 24 c having a C-shaped (or U-shaped) cross-section as illustrated in FIG. 7C. Further, the columnar member may be a columnar member 24 d having a cross-shaped cross-section (a cross-section with a stepped shape on the upstream side) as illustrated in FIG. 7D. Further, the columnar member may be a columnar member 24 e having a flat plate-like cross-section facing the flow as illustrated in FIG. 7E. Further, the columnar member may be a columnar member 24 f having a chevron cross-section with a slit in a central portion thereof as illustrated in FIG. 7F.

As illustrated in FIGS. 2, 5, 7A, 7B, 7C, and 7D, the columnar member preferably has a cross-sectional shape that is convex toward the upstream side of the flow of the cooling fluid in the horizontal plane. Since the cross-sectional shape of the columnar member in the horizontal plane is convex toward the upstream side of the flow of the cooling fluid, the jet of the cooling fluid from the inflow pipe can be effectively divided and dispersed in the horizontal direction. Further, the jet of the cooling fluid from the inflow pipe is suppressed from hitting the columnar member hard and bouncing vertically upward. As a result, the effect of suppressing the turbulence of the liquid surface of the cooling fluid is improved.

Further, from the viewpoint of dividing the flow of the cooling fluid more smoothly to suppress the division of the bubbles, it is preferred that the columnar member has a rounded shape at a corner of a portion facing the flow of the cooling fluid (a shape in which a corner of an outer peripheral surface is rounded) as illustrated in FIGS. 7A and 7C. For example, it is preferred that the corner of the uppermost stream portion of the columnar member and/or both side end portions (an upper end portion and a lower end portion in FIGS. 7A to 7C) of the columnar member are rounded. If these portions are rounded, even when the jet of the cooling fluid hits the columnar member, and thus the flow of the cooling fluid is divided, generation of a vortex is suppressed around the columnar member. Therefore, it is possible to suppress the bubbles in the cooling fluid from being finely divided by the vortex and from being difficult to be separated.

Further, as illustrated in FIGS. 2, 5, 7A, 7C, and 7F, in the columnar member, it is preferred that the cross-sectional shape in the horizontal plane is formed such that the width of the columnar member (when viewed along the center line of the inflow pipe) at the upstream side of the flow of the cooling fluid is smaller than that of the columnar member at the downstream side of the flow of the cooling fluid. Further, it is particularly preferred that the cross-sectional shape of the columnar member in the horizontal plane is such that the width of the columnar member increases toward the downstream side. When the columnar member has such a cross-sectional shape, the effect of division and dispersion of the cooling fluid by the columnar member is more remarkable. Therefore, the effect of suppressing the turbulence of the liquid surface of the cooling fluid is improved.

The columnar member may have a surface that faces substantially perpendicular to the jet of cooling fluid from the inflow pipe, as illustrated in FIGS. 7C, 7D, and 7E. However, such a surface also causes the jet to bounce vertically upward and the liquid surface of the cooling fluid to undulate. Therefore, it is preferable to make the width of such a surface as narrow as possible.

Further, as illustrated in FIG. 7F, when the columnar member is the columnar member 24 f having a slit in the central portion, the jet of the cooling fluid from the inflow pipe can be divided and dispersed substantially in three directions by the columnar member 24 f. Therefore, the effect of division and dispersion of the cooling fluid by the columnar member is more remarkable. Therefore, the effect of suppressing the turbulence of the liquid surface of the cooling fluid is improved. The size of the slit is adjusted so that the jet passing through the slit is appropriately weakened.

FIG. 8 illustrates a reservoir tank 30 of a third embodiment. FIG. 8 is a vertical cross-sectional view of the reservoir tank 30 corresponding to FIG. 1 in the first embodiment. The reservoir tank 30 of the third embodiment is different from the reservoir tank 10 of the first embodiment, in the shape of the tank body 37, the shape and arrangement of the columnar member 24 c, and the position of the discharge pipe 36. Other configurations of the reservoir tank 30 are the same as those of the reservoir tank 10 of the first embodiment.

In the reservoir tank 10 of the first embodiment illustrated in FIG. 1, the shape of the tank body 17 is a rectangular parallelepiped shape. On the other hand, in the reservoir tank 30 of the third embodiment, the shape of the tank body 37 is spherical. The shape of the tank body 37 is not particularly limited, and may be another shape such as a cylindrical shape, an elliptical cylindrical shape, or an ellipsoidal shape.

Further, in the reservoir tank 30 of the third embodiment, the columnar member 24 c has a C-shaped (arcuate) cross-section as illustrated in FIG. 7C. The columnar member 24 c is disposed so that its cross-section is convex toward the upstream side of the flow of the cooling fluid. Further, in the present embodiment, the columnar member 24 c is erected like the cantilever.

As in the reservoir tank 10 of the first embodiment illustrated in FIG. 1, even in the reservoir tank 30 of the third embodiment, the columnar member 24 c extends in the substantially vertical direction when viewed along the center line m of an inflow pipe 35. Thus, the jet of the cooling fluid from the inflow pipe is divided and dispersed substantially horizontally. Therefore, the effect of suppressing the turbulence of the liquid surface of the cooling fluid is remarkable.

Further, in the reservoir tank 30 of the third embodiment, as illustrated in FIG. 8, the columnar member 24 c is provided such that the columnar member 24 c is inclined with respect to the center line m of the inflow pipe 35 when viewed from a direction perpendicular to both the center line m of the inflow pipe 35 and the vertical direction. More specifically, the columnar member 24 c is provided inclined so that a distance between the inflow pipe 35 and the columnar member 24 c measured in a direction along the center line m of the inflow pipe 35 is reduced as it moves away from a lower base (a joint portion of the columnar member 24 c with the tank body 37) of the columnar member 24 c.

When the columnar member 24 c is inclined in this way, and the jet of the cooling fluid hits the columnar member 24 c, the jet tends to be directed slightly vertically downward. Therefore, the effect of suppressing the turbulence of the liquid surface of the cooling fluid is more remarkable.

FIG. 10 illustrates a reservoir tank 40 of the fourth embodiment. FIG. 10 is a vertical cross-sectional view of the reservoir tank 40 corresponding to FIG. 1 in the first embodiment. The reservoir tank 40 of the fourth embodiment is different from the reservoir tank 10 of the first embodiment, in a position and shape of the inflow pipe (an outer pipe 451 and an inner pipe 452) and a shape of a columnar member 44. Other configurations such as a position of a discharge pipe 46 in the reservoir tank 40 are the same as those of the reservoir tank 10 of the first embodiment.

In the reservoir tank 40 of the fourth embodiment, the inflow pipe is extended inside the tank body 47. That is, in the present embodiment, the inflow pipe has the outer pipe 451 provided outside the tank body 47 and the inner pipe (an extension portion) 452 provided inside the tank body 47. The outer pipe 451 and the inner pipe 452 are connected to each other to form a single pipe line. Note that the inner pipe 452 may share a part of the wall surface with the tank body 17.

The extension portion of the inflow pipe, that is, the inner pipe 452 is opened to an inner space of the tank body 47 vertically below the liquid level S of the cooling fluid stored inside the tank body 47. With such a configuration, the flow of the cooling fluid flowing therein from the inflow pipe flows directly into the cooling fluid stored in the tank (that is, without passing through the air). Therefore, the effect of suppressing the turbulence of the liquid surface of the cooling fluid is secured. The inner pipe 452 may have a portion such that the pipe line extends in the substantially vertical direction as in the present embodiment.

Further, in the present embodiment, the columnar member 44 extends in the substantially vertical direction when viewed along the center line m of the pipe line of the inflow pipe at a portion where the inflow pipe (inner pipe 452) is opened to the inner space of the tank. Further, a part of the columnar member 44 is disposed on the extension line of the center line m of the pipe line of the inflow pipe at the portion where the inflow pipe (inner pipe 452) is opened. That is, the inner pipe 452 is formed so that the flow of the cooling fluid passing through the pipe line is directed to the columnar member 44. Although not essential, in the present embodiment, it is preferred that the center line m of the pipe line at the portion where the inflow pipe (inner pipe 452) is opened to the inside of the tank body extends in the substantially horizontal direction. In this case, the cooling fluid flowing from the inflow pipe (inner pipe 452) into the tank body flows in the substantially horizontal direction toward the columnar member 44.

In the reservoir tank 40 of the fourth embodiment, the inflow pipe is extended inside the tank body 47. Further, the inflow pipe is opened to the inner space of the tank body 47 vertically below the liquid level S of the cooling fluid stored inside the tank body 47. In this case, unlike the first to third embodiments, it is not essential that the inflow pipe is connected to the tank body 47 vertically below the liquid level S of the cooling fluid stored inside the tank body 47. It is because, in the fourth embodiment, the inner pipe 452 functions as the extension pipe of the outer pipe 451, that is, the inflow pipe having the inner pipe 452 functions in the same manner as the inflow pipe connected to the tank body 47 below the liquid level S of the cooling fluid.

As in the reservoir tank 10 of the first embodiment illustrated in FIG. 1, even in the reservoir tank 40 of the fourth embodiment, the columnar member 44 extends in the substantially vertical direction when viewed along the flow of the cooling fluid toward the columnar member 44 (in a direction of the center line m in FIG. 10). Therefore, the flow of the cooling fluid from the inflow pipe hits the columnar member 44. Thus, the jet of the cooling fluid from the inflow pipe is divided and dispersed substantially horizontally. Therefore, the effect of suppressing the turbulence of the liquid surface of the cooling fluid can be obtained.

Further, in the reservoir tank 40 of the fourth embodiment, the inflow pipe is provided to extend inside the tank. Thus, it is possible to obtain the effect of suppressing the turbulence of the liquid surface of the cooling fluid while increasing the degree of freedom in arranging the portion (the outer pipe 451) of the inflow pipe located outside the tank body 47. That is, according to the reservoir tank 40 of the fourth embodiment, the inflow pipe (outer pipe 451) may be disposed at a position vertically higher than the liquid level S of the cooling fluid. Therefore, the degree of freedom in layout of the reservoir tank is increased.

The reservoir tank according to the embodiment of the present disclosure may have other structures. For example, the reservoir tank may be provided with a removable cap. Through such a cap, the cooling fluid can be filled in the tank or the cooling fluid circuit. Further, the cap may be provided with a pressure release valve. Further, a stay or a boss member for attaching the reservoir tank to a vehicle body or the like may be integrated with the reservoir tank as necessary. Furthermore, the reservoir tank may be provided with a reinforcing structure such as a rib depending on a pressure resistance required for the reservoir tank.

INDUSTRIAL APPLICABILITY

The reservoir tank according to the embodiments of the present disclosure can be used in the cooling fluid circuit of the cooling system. The reservoir tank according to the embodiment of the present disclosure has high industrial utility value because it can suppress the generation of the bubbles in the cooling fluid.

Further, the reservoir tank according to the embodiment of the present disclosure may be the following first and second reservoir tanks.

The first reservoir tank is a reservoir tank provided in the cooling fluid circuit of the liquid-cooled cooling system, and includes: a tank body in which cooling fluid is stored; an inflow pipe for sending the cooling fluid into the tank body; and a discharge pipe for discharging the cooling fluid from the tank body, in which the inflow pipe is connected to the tank body vertically below a liquid level of the cooling fluid stored inside the tank body, a columnar member is erected inside the tank body, the columnar member extends in a substantially vertical direction when viewed along a center line of the inflow pipe, and a part of the columnar member is disposed on an extension line of the center line of the inflow pipe.

The second reservoir tank is a reservoir tank provided in the cooling fluid circuit of the liquid-cooled cooling system, and includes: a tank body in which cooling fluid is stored; an inflow pipe for sending the cooling fluid into the tank body; and a discharge pipe for discharging the cooling fluid from the tank body, in which the inflow pipe extends inside the tank body and is opened to an inner space of the tank body vertically below a liquid level of the cooling fluid stored inside the tank body, a columnar member is erected inside the tank body, the columnar member extends in a substantially vertical direction when viewed along a center line of a pipe line of the inflow pipe at a portion where the inflow pipe is opened, and a part of the columnar member is disposed on an extension line of the center line of the pipe line of the inflow pipe at the portion where the inflow pipe is opened.

The foregoing detailed description has been presented for the purposes of illustration and description. Many modifications and variations are possible in light of the above teaching. It is not intended to be exhaustive or to limit the subject matter described herein to the precise form disclosed. Although the subject matter has been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims appended hereto. 

What is claimed is:
 1. A reservoir tank comprising: a tank body in which cooling fluid is stored; an inflow pipe for sending the cooling fluid into the tank body; a discharge pipe for discharging the cooling fluid from the tank body; and a columnar member erected inside the tank body, wherein the inflow pipe is connected to the tank body vertically below a liquid level of the cooling fluid stored inside the tank body, the columnar member extends in a substantially vertical direction when viewed along a center line of the inflow pipe, and a part of the columnar member is disposed on an extension line of the center line of the inflow pipe.
 2. The reservoir tank according to claim 1, comprising a plurality of the columnar members including a first columnar member and a second columnar member, wherein the plurality of columnar members is arranged so that a flow of the cooling fluid flowing from the inflow pipe into the tank body is divided in a substantially horizontal direction by the first columnar member, and the divided flow of the cooling fluid is further divided in the substantially horizontal direction by the second columnar member.
 3. The reservoir tank according to claim 1, wherein a position in which the extension line of the center line of the inflow pipe and the columnar member intersect is vertically below the liquid level of the cooling fluid.
 4. The reservoir tank according to claim 3, wherein the center line of the inflow pipe extends in a substantially horizontal direction, and the columnar member extends in a substantially vertical direction.
 5. The reservoir tank according to claim 1, wherein the columnar member is disposed to connect a top wall and a bottom wall of the tank body.
 6. The reservoir tank according to claim 1, wherein a cross-sectional shape of the columnar member in a horizontal plane is convex toward an upstream side of a flow of the cooling fluid.
 7. The reservoir tank according to claim 1, wherein a width of the columnar member when viewed along the center line of the inflow pipe is 0.5 times or more and 3 times or less a diameter of the inflow pipe.
 8. A reservoir tank comprising: a tank body in which cooling fluid is stored; an inflow pipe for sending the cooling fluid into the tank body; a discharge pipe for discharging the cooling fluid from the tank body; and a columnar member erected inside the tank body, wherein the inflow pipe extends inside the tank body and is opened to an inner space of the tank body vertically below a liquid level of the cooling fluid stored inside the tank body, the columnar member extends in a substantially vertical direction when viewed along a center line of a pipe line of the inflow pipe at a portion where the inflow pipe is opened, and a part of the columnar member is disposed on an extension line of the center line of the pipe line of the inflow pipe at the portion where the inflow pipe is opened. 